Elastic energy and string configurations in the chiral gauge theory of biaxial uniaxial nematic phase transitions

In nematic liquid crystals (NLCs), topological defects of a chiral origin play a role in phase transitions and lead to phase configurations of nontrivial topology, like those in neutron stars and helium in the A-phase. In the biaxial-uniaxial phase transition, the deformation of the orbit, as the order parameter degeneracy of the NLC, connects together an evolution of topological defects, the surface anchoring energy and elastic Frank modui. In this work we estimate the chiral gauge field presentation of the constrained Ladnau-de Gennes theory of the biaxial nematics, which have to explain their topologically dependent phase transformation, using the description of the transformation of disclinations in the biaxial nematic phase into the surface bojooms of a uniaxial NLC.Comment: 5 pages, 2 figure

Lattice analogy of area-difference elasticity model for lipid-detergent bilayer vesiculation

The vesiculation process was examined in the lipid-detergent solution (dimyristoyl-sn-glycero-phoshatidylcholine/octaethylleneglycol n-dodecyl ether/water), using small-angle neutron scattering experiments \cite{1}. When observing vesiculation proceeds from rod-like micelles to unilamellar vesicles, the transformation is induced by jump-like temperature increase and a monotonic increase in detergent concentration. Our numerical estimations of the vesicle shape parameters (the elasticity coefficients and its fraction on a macroscopic scale) are based upon the area-difference elasticity model \cite{2, 3}. Thus, we composed the numerical Monte Carlo method, which connects the macroscopic and microscopic scales by the concept of self-avoiding random surfaces.Comment: 2 figs, fig. 1 and title changed, after correction and titled "Numerical version of area-difference elasticity model for lipid-detergent bilayer vesiculation" accepted to MSE-A (Elsevier

Phase heterogeneities of lipidic aggregates

We propose a model for explanation the "domain-wall" type configuration states in binary lipid mixtures of cationic and neutral lipids, associated with observed relaxation effects in their aggregates. We apply the analogy with formation of Kibble-\.Zurek topological defects, which we suppose connected with structural dynamics of the lipid phases. In frames of the proposed model, the density of kink-type defects and the energy of the configurations are calculated.Comment: in final form to SS

Comments to topological defects in bilayer vesicles

To explain the details of bilayer vesicle aggregation, we revised the anyon model for lipid domains formation in closed vesicles of lipid-cholesterol system $DPPC/DLPC$/cholesterol, which was measured by Feigenson and Tokumasu (Biophys. Journal, 2001, 2003) in frames of the different optical experiments and atomic-force microscopy.Comment: 2 p

Spin glass transitions of smectic-AA crosslinked elastomers

Elastomers are artificial polymeric materials created for industrial and commercial applications. Depending on their purpose, they are performing in different species and structure modifications. Our studies focus on the systems of elastomers randomly standing-distributed in a smectic $A$ (Sm$A$) liquid crystal. Basing on the suggestion following from the experiment, that at a phase transition from Sm$A$ to nematic phase caused by an increase of a crosslink concentration, such a system survives a percolation transition at low crossilink concentrations, we propose a modeling explaining this phenomena. We approve the three-dimensional Villain spin glass model and apply lattice Monte Carlo (MC) techniques on differential forms on a dual lattice, that is an alternative of a replica trick, developed for nematic elastomers in the 3D XY universality. In the results of that we have confirmed a concentration phase transition of percolation nature at a small crosslink concentration ($\sim$ 10 weight %).Comment: 5.3 pages, 7 figures, revised, reported at ICIFMS-1

Lattice model calculations on aqueous acetone and tetramethyl urea

In frames of the Ising model, we analyze self-organization of aqueous acetone (AC) and tetramethyl urea (TMU), caused by lyotropic phase transformations. Using the lattice Monte Carlo simulations, we confirmed the statements by Koga and co-workers on the tree content dependent mixing schemes in AC and TMU and found the values of molar fractions of surfactants, corresponding to the transitions between the mesophases of these mixing schemes. So we may compare these results with another concepts on the water structures.Comment: minor revision, partially submit to Revue Roumaine de Chimi

Elastic properties of vanadium pentoxide aggregates and topological defects

We study the aqueous solution of vanadium pentoxide by using topology methods. The experiments by Zocher, Kaznacheev, and Dogic exhibited, that in the sol phases of $V_2O_5-H_2O$, the tactoid droplets of $V_2O_5$ can coalesce. In the magnetic field, this effect is associated with a gauge field action, viz. we consider coalescence (in the topologically more convenient term, "junction") of droplets as annihilation of topological defects, concerning with the tactoid geometry. We have shown, that in the magnetic field, the tactoid junction is mainly caused by non-Abelian monopoles (vortons), whereas the Abelian defects almost do not annihilate. Taking into account this annihilation mechanism, the estimations of time-aging of the $V_2O_5-H_2O$ sols may be specifiedComment: original title was "The junction of tactoids in lyotropic inorganic liquid crystals" final for

Elasticity in the Gauge Theory of Active Nematics with Topological Defects

We analyze the phase behavior of lyotropic nematic liquid crystals in the self-organizing flow, viz. so called active nematics (AN). Their elastic properties are mutually caused by evolution of topological defects (for instance, disclinations and boojums) and the flow regime. Such changes in elasticity of AN comparing with conventional inactive ones set the new working characteristics of these materials, have an influence on their switchable and tunable properties. In this work, we study the uniaxial droplet AN phases with topological defects in their collective flow, we apply the gauge string-like theory using the method of differential forms on a lattice interchanging the drive-force concept. The results of our numerical modeling with Monte Carlo method show, that under certain conditions, the type of the phase transition from nematic to isotropic (N-I) phase and the thermodynamical characteristics in an active regime may differ from such one in the conventional lyotropic nematcis.Comment: 1 figure, conference paper, add reference

Analytical evidence for quantum states in aqueous vanadium pentoxide with positron lifetime spectroscopy

The possibility of registration of quantum states, such as the coalescence of droplets (tactoids) in the sol phase of aqueous vanadium pentoxide V$_2$O$_5$, with positron annihilation lifetime spectroscopy is discussed. The decrease of the long-living positronium (Ps) lifetime term in the result of the coalescence of V$_2$O$_5$ tactoids is predicted.Comment: 1 figur

Size of nanoobjects in oil and gas species and materials with positron annihilation spectroscopy

The analytical method to determine geometry and size of nano-scale defects in oil and gas species and materials is proposed. The modeling is carried out with the parameters of the positron spectra in the angular distribution method of positron annihilation spectroscopy, and is based on the 'free electron' approximation. From the annihilation decay kinetics, it is possible to express the trapping velocity of parapositronium in pores via intensities of the positronium components and to define the concentration and radii of pores in a porous layer. As the result, size and the concentration of micro-porous cylindrical nano-objects in the silicon samples are estimated.Comment: 6 pages, 2 table